(5 of )Dale Earnhardt Jr. looks on in the garage during practice for the NASCAR Cup series auto race, Saturday, June 3, 2017, at Dover International Speedway in Dover, Del. (AP Photo/Nick Wass)

(6 of )Dale Earnhardt Jr. (88) approaches the start/finish line during practice for the NASCAR Cup Series race at Richmond International Raceway in Richmond, Va., Friday, April 28, 2017. (AP Photo/Steve Helber)'

(7 of )Dale Earnhardt Jr. in action during the NASCAR Cup Series Pocono 400, Sunday, June 11, 2017, in Long Pond, Pa. (AP Photo/Matt Slocum)

In motorsports, when someone says “Junior,” there’s no doubt who that means.

One of the most popular stars the sport has ever known, Dale Earnhardt Jr. will make the last Sonoma Raceway appearance of his career next weekend in the Toyota/Save Mart 350.

After suffering two concussions in four years and missing 18 races last season with the aftereffects, the man who saw his father die in a 2001 crash is hanging up his fire suit at the end of this season.

He’s 42.

That’s seven years younger than his father, Dale Sr., was when he was killed in a final-lap wreck at the Daytona 500 — a crash that happened seconds behind Junior as he battled for the checkered flag.

It’s only three years younger than his grandfather, Ralph Earnhardt, was when the 1956 NASCAR Sportsman Champion died of a heart attack.

As the Monster Energy NASCAR Cup Series returns to Sonoma, Junior will mark his 18th and final race in Wine Country.

He will be searching for an elusive win at the road course after finishing in the top 10 two of the previous three years.

And undoubtedly, fans will turn out in droves to pay their respects to the man voted most popular driver for the last 14 years.

There will be two practice sessions Friday, qualifying on Saturday and the 110-lap Toyota/Save Mart 350 on Sunday.

No public events or autograph sessions with Earnhardt are planned, though admirers will surely pack the stands and the new fan party area RevZone at Turn 7 to see the No. 88 car out with style.

“The name is magic in this industry,” Sonoma Raceway general manager Steve Page said. “His father was a legend; his grandfather was a legend. So the name Earnhardt and NASCAR are so indelibly linked that when he came, whether a blessing or curse, he came with the moniker that denotes so much history in the sport.”

Earnhardt said Sonoma Raceway is one of the most difficult tracks to drive, one of only two road courses in the Cup Series season.

“If we ever win there, man, would that be a shock,” he said earlier this year.

“We celebrated a top 10 at Sonoma with more energy and intensity than we celebrate wins anywhere else,” he told race officials. “We went home after a third place a couple years ago (2014) and partied harder than we did when we won the Daytona 500.”

Discussing the 10-turn, 1.99-mile course, he said it was one of the most physically demanding races of the year. Instead of making left turns on an oval all afternoon, Sonoma’s road course is composed of turns, straightaways, areas of breaking and accelerating, and yes, turning right.

“You’re using a lot of muscles in your body you don’t (normally) because you’re turning right, a lot of things in your neck and back that you don’t typically use are getting used. And you’re just not ready for it,” Earnhardt said.

“The heat’s intense and it’s just a really difficult, challenging race. To come out of there with any kind of result in the top 10, I’m like, ‘Heck yes, let’s get outta here.’”

Maybe it’s in the cards. Another crowd favorite, Tony Stewart, did it last year.

In his retirement season, Stewart ended an 84-race winless streak and posted the final victory of his Cup Series career here on a dramatic last-turn pass of Denny Hamlin.

Since announcing his retirement in April, Earnhardt has received a number of farewell gifts from fans and commendations from those in the field of concussion research about his willingness to discuss his health and his rehabilitation from the head injuries.

“It’s awesome to have that opportunity to be able to get people in front of the right doctors and get them the right help,” he said in announcing his decision.

“I had some people come out of the woods wondering, ‘Where do I get this help?’ And then to hear their success stories and to hear them ... get the help they’ve been looking for all these years. It’s been a tremendous experience for me.”

Earnhardt was born into a racing family that was already two generations in.

His father was a seven-time NASCAR champion and one of the most popular drivers in a sport ruled by hard-bitten macho country boys like Cale Yarborough, Darrell Waltrip, Richard Petty (nicknamed “The King”) and Earnhardt, who earned the moniker “The Intimidator” for his hard-charging style.

Earnhardt’s maternal grandfather, Robert Gee, was a NASCAR engine builder.

As a youth, Junior worked at his father’s car dealership, learning basic repairs and maintenance before they let him get behind the wheel of a race car.

In his retirement announcement, he said he didn’t have wild dreams of winning big races or setting records.

“I knew the odds of me having any talent at all were thin. They are for anyone,” he said. “I just wanted to do it. I just wanted to be able to do it.”

In his early 20s, he was driving late-model stock cars — not very successfully. He’d run in 159 races, winning only four.

Soon, his father told him the funds for that effort had “dried up.”

By 1999 at age 25, he was racing in the NASCAR Cup Series and in 2000, he notched two Winston Cup victories and won nearly $3 million in prize money.

“A lot of people don’t know this, but it’s all for my daddy,” Earnhardt told The New York Times in 1999. “I win races to put smiles on his face.”

Over the next decade, Earnhardt won 16 races, had 144 top-10 finishes and totaled more than $60.6 million in earnings.

He is a two-time Daytona 500 winner, having won a decade apart, in 2004 and 2014.

Earnhardt has won the Most Popular Driver award 14 times in a row, from 2003 to 2016, during a time the sport has seen a dramatic decline in TV viewership.

According to Nielsen, NASCAR viewership has fallen 45 percent since 2005, from nearly 9 million viewers per race to 4.6 million last year.

The retirements of popular drivers including California native Jeff Gordon in 2015, the fiery Stewart in 2016 and now Earnhardt add another challenge to a sport that at one point had visions of challenging the NFL for popularity.

Asked if leaving his sport at such a crossroads factored in his decision to retire, Earnhardt said he has high hopes that some of the young, charismatic drivers will spark a resurgence in the sport’s popularity.

Two of the top drivers in the standings are Kyle Larson, 24, and Chase Elliott, 21 — both of whom Earnhardt name-dropped as possible torch-bearers.

It’s a generational transition that happens in every sport.

“The good thing that we’re seeing this year is the emergence of this next generation of drivers that have been lingering on the sidelines,” Page said.

Larson on Friday landed the pole position for today’s Firekeepers Casino 400 at Michigan International Speedway.

“There is a group of young stars that are very, very talented drivers that will be the stars of tomorrow,” Page said. “It will be fun to see them step forward, have success and build their followings.”

Earnhardt said the time off last year spent rehabbing from his most recent concussion — suffered in a June 2016 crash at Michigan International Speedway, although he said he didn’t realize it at the time — changed his perspective on his career and life priorities.

He missed the final 18 races of 2016 because of the injury. He also missed two races in 2012 because of two concussions in a six-week period.

For months, he fought balance and stability issues and vision problems. And he was forced to seriously consider he might never race again.

Maturing from an emotional young driver to elder statesman of the sport to a post-track life has been a journey, Earnhardt said.

“As you get older, you start to enjoy being at the track, driving the car, because you don’t know how many more opportunities you will have to do that, enjoy doing it instead of making yourself miserable doing it,” he said.

Although he didn’t say it, his father and grandfather’s relatively early deaths may have played a role in his decision.

“I just wanted the opportunity to go out on my own terms,” he said. “I just wanted to be able to make that decision myself on retiring and not have it made for me.”

He said he intends to remain in the sport and is actively involved in his family’s business and Hendrick Motorsports, under whose umbrella he drives. He says he doesn’t “have to be the one holding the trophy.”

“My heart loves being in the car. I love driving and I enjoy it as much as I always have,” he said. “I do have ambition to work. I’m not going to quit working. There’s a feeling of being an asset to something.”

Earnhardt has said he plans to drive in two races next year in the lower-level Xfinity Series, in which he is a team owner.

He married his longtime girlfriend, Amy Reimann, on New Year’s Eve, and has talked about starting a family. While he was out last year, he served as a TV commentator for a handful of races.

During the weekend, Sonoma Raceway officials will unveil a special gift for Earnhardt involving a Sonoma County nonprofit.

You can reach staff writer Lori A. Carter at 707-521-5470 or lori.carter@pressdemocrat.com.